1. Field of the Invention
This invention relates to mechanical blood coagulation on endogenous hard body such as bone tissue, for example, employing improved resorbable wax compositions and methods.
2. Discussion of Relate Art
This application is a continuation-in-part of application U.S. Ser. No. 06/700,351 filed Feb. 19, 1985, which is, in turn, a continuation-in-part of application U.S. Ser. No. 06/470,075, filed Feb. 28, 1983, now abandoned.
Published German Patent application P 32 29 540.5 represents the priority document on which the above identified parent applications are based.
For mechanical blood coagulation on endogenous hard body tissues, such as bone, for example, it is customary to treat resected bone parts with bone wax. For the same reason, blocks of bone wax are also used to cover spaces filled with spongiosa.
The waxy masses used up to the present time were made, for example, of beeswax, almond oil and salicylic acid, or beeswax and isopropyl palmitate. Relevant literature includes, for example,
Douglas, B. L.: Oral Surg., Vol. 6, p.1195, 1953;
Selden, H. S.: Oral Surg., Vol. 29, p. 262, 1970;
Shields, T. W.: General Thoracic Surgery, Lea and Febiger, Philadelphia, 1972; and
Wolter, D. et al.: Chirug., Vol. 46, p. 459, 1975.
In general, postoperative healing proceeds without disturbance; bacterial contamination is rare.
Commonly, however, in the case of the bone waxes used for coagulation during surgery up to the present time, coverage of the implant by granulation tissue containing abundant macrophages and giant cells is observed, see D. Wolter et al., op eit. The granulation tissue becomes fibrotic within the body with the passage of time.
Direct contact between the bone and the wax does not occur. Nonspecific foreign body reactions often take place at the spongiosa/bone wax contact zones. This inhibits the new formation of bone and promotes the development of pseudoarthroses, see
Geary, I. R. et al.: Ann. Surg., Vol. 132, p. 1128, 1950 and
Howard, C. C. et al.: Clin. Orthop., Vol. 63, p. 226, 1969.
High molecular weight polymers and their use in the medical sector are known. They have fiber properties. Their tolerance and degradability have been studied in detail. Well known, for example, are synthetic filament materials, resorbable with the body, based on polyglycolic acid and polylactic acid; see for example, U.S. Pat. Nos. 3,297,033; 3,626,948; 2,668,162; 2,676,945 and 2,703,316.
Published German patent application P32 29 540.5 relate to resorbable waxes for mechanical blood coagulation on hard body tissue, more especially on bones, which consist of wax-like polyester oligomers of lower hydroxycarboxylic acids. These materials range from viscous to solid at body temperature. By virtue of their structure, these waxes are degradable by the body's own metabolic processes, the degradation rate being adjustable in known manner. The preferred waxes have average molecular weights of about 200 to 1500 and, more especially, of about 300 to 1000.
Corresponding polyester oligomers of lactic acid and/or glycolic acid are described as being particularly suitable. According to the published German patent application cited above, monofunctional and/or difunctional alcohols or carboxylic acids or carboxylic anhydrides and/or primary or secondary monoamines may be used to regulate the average molecular weight of the polyester oligomers. A definitive average molecular weight may be determined in advance in a known manner by selecting suitable mixing ratios of oxycarboxylic acids and additional monofunctional or difunctional component. It is known that the reaction products obtained are not uniform in their degree of oligomerization and still contain certain quantities of the starting components.